1. Field of the Invention
The present invention relates to a fuel system for a traveling vehicle having an engine mounted on a vehicle body and a rollover protection structure (ROPS) extending upward from the vehicle body.
2. Description of the Related Art
There is known a vehicle having a fuel gas recovery (collecting) apparatus including a canister incorporated in a gas passageway between a fuel tank and an engine, so that fuel gas is adsorbed by e.g. activated carbon and this adsorbed fuel gas is desorbed during driving of the engine (see e.g. JP 2008-008238 A, and JP 2009-067144 A or U.S. 2009/239706 A1 corresponding thereto).
The canister is utilized for causing fuel gas evaporated inside the fuel tank during stop of the engine (in particular, during fuel supplying operation) and the adsorbed gas is desorbed during driving of the engine and combusted, so as to restrict undesired discharge of the fuel gas (evaporated gas) evaporated inside the fuel tank into the atmosphere.
In JP 2008-008238 A, the canister is disposed upwardly of the fuel tank and connected thereto via a breather pipe. When the liquid surface inside the fuel tank is under the full (or nearly full) condition, in consideration of variation of the liquid level which occurs e.g. when the self-propelled vehicle body is inclined to the front/rear or right/left side or during acceleration, braking or turning, etc. of the vehicle (these conditions will be referred generically to as “time of vehicle body inclination” hereinafter), a portion of the gas passageway (reserve pipe) extending and communicated to the canister is disposed at a position higher than the maximum level position reachable by the liquid surface, so as to prevent liquid fuel from entering the canister.
In the case of JP 2009-067144 A (U.S. 2009/239706 A1), in a work vehicle having a ROPS (rollover protection frame), the canister is disposed immediately above the fuel tank, and the fuel tank and the canister are connected via a vapor introducing tube incorporating a two-way valve halfway thereof, so that evaporated fuel inside the fuel tank may be supplied to the canister.
In the case of JP 2008-008238 A, the canister is disposed upwardly of the fuel tank and these two are connected to each other such that a purging hose or evaporating hose may pass a position higher than the variable liquid surface level. So, even when the self-propelled vehicle body is inclined significantly, liquid fuel may not move into the canister. In this type of technique, if liquid fuel should move to the side of the canister, this will adversely affect the function of the activated carbon inside the canister.
Therefore, in the case of the work vehicle having a ROPS disclosed in JP 2009-067144 A (U.S. 2009/239706 A1) too, the canister is disposed upwardly of the fuel tank and the vapor introducing tube interconnecting the fuel tank and the canister is connected with taking partially upward detour. The reason for this arrangement is the same as that for JP 2008-008238 A (i.e. for preventing movement of liquid fuel into the canister due to vehicle inclination).
It is sometimes desirable to dispose the canister not immediately upwardly of the fuel tank, but distant therefrom. Also, the fuel tank may be elongate in the front/rear direction or has a large width. Or, a pair of fuel tanks may be disposed in distribution on the right/left sides. In such cases, the canister is sometimes disposed at positions not upwardly of the fuel tank. In these cases, the variable liquid surface level will become higher with inclination of the self-propelled vehicle body. Therefore, in such cases, it becomes necessary to provide separately a support member for raising the evaporating hose to an even higher position or make some arrangement for preventing the elevation of the variable liquid surface level between the fuel tank and the canister.
In view of the above, the object of the present invention is to prevent inadvertent entrance of fuel liquid in the fuel tank to the side of the canister, even in the event of significant inclination of the self-propelled vehicle body.